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Matt, Engineer
Category: BMW
Satisfied Customers: 21375
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
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2012 bmw x5 v8, 3100 code and 2abc, reset but still come

Customer Question

2012 bmw x5 v8
JA: What are all the symptoms you've noticed (e.g. noises, leaks, flashing lights, error codes)?
Customer: 3100 code and 2abc
JA: Just to clarify, what's the exact code? And have you tried to reset it?
Customer: reset but still come back
JA: Are you fixing your X5 yourself? What have you tried so far?
Customer: yes i try to fix it
JA: Anything else you want the mechanic to know before I connect you?
Customer: nope
Submitted: 9 months ago.
Category: BMW
Expert:  Matt replied 9 months ago.


that code is boost control deactivated


I'd first checkall the high pressure hoses post turbo/s for any split hoses or cracked metal pipes, also check the ends of the intercooler as its not unheard of to pop the end caps off under high boost.

If this is OK then check the small vacuum lines to the turbo and its connected control solenoid on the bulkhead, any cracks or leaks can give turbo issues

Also have a feel around with your bare hands with the engine running to see if you can feel any escaping gas under your touch. Another method is to use a soap and watersolution sprayed onto any suspect areas - if there's a leak it'll bubble up with the engine running

Also check that the vacuum hose running to the dump /turbo bypass valve is intact with no leaks as if the dump valve is opening prematurely you'll be losing all your boost

If this is OK then remove the high pressure intake hose after the turbo and have a feel of the turbine wheel - there should be no play radially at all -but a little bit of axial / end to end float is normal

one other possibility is that the wastegate actuator spring has gone soft so allowing the wastegate to open prematurely - if your actuator has a threaded end you can increase the preload on it to see if this improves things otherwise these units are quite cheap compared to a new turbo so it may be worth trying a replacement

If this is OK then check for air leaks after the mass airflow meter - The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane around each joint in turn. If the engine rev's up you've found your leak.

Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.

Customer: replied 9 months ago.
have u some diagram for the vaccum solenoid? when i pull out the vaccum line ,touche with my finger no suction on it. But check the vaccum line come from the pump,that line have suction.
Expert:  Matt replied 9 months ago.


the boost control solenoid will have 2 hose connections

1 running from the engine inlet manifold , the other to turbo

the manifold side should have vacuum with a running engine and the other side only have vacuum when its trying to control boost / open the wastegate

if the vacuum hoses are on back to front then you will have issues with boost control

so it may be worth swapping them over to see if that helps

Customer: replied 9 months ago.
i mean the wire diagram for the test wire ?
Expert:  Matt replied 9 months ago.


the boost solenoid will only have 2 wires going to it

1 will run to earth

the 2nd will run to the ECU and be powered up with a fluctuating 12V signal

its the speed of the fluctuation that controls the amount the valve opens and how much the wastegate is opened

or did you mean something else

Customer: replied 9 months ago.
ok thx i try to put back all the cooler and connetor and do the test see what happend
Expert:  Matt replied 9 months ago.


just get back to me on this post

Customer: replied 9 months ago.
did u have the wire diagram with the color of the wire,i am not sure it s the i put the right plug or not too much same connection on it ,but the longer not the same,that will ne rare to be wrong ,just for make sure i need the color code of the plug for the solenoid booster
Customer: replied 9 months ago.
the code always here even the car no star just key on, i use scanner to clear code cannot be clear,so i think maybe some connector probleme?
Expert:  Matt replied 9 months ago.


the WG solenoid should look like the one in the image

and yes I'd agree if you can't clear the code then its either a wiring fault or a fused solenoid

you can test the solenoid by disconnecting the solenoid and then applying 12V across it ( the solenoid should be marked +ve & -ve)

Customer: replied 9 months ago.
i know the solenoid both stick together, i mesure the curent it was 11volt key on.
Expert:  Matt replied 9 months ago.


OK so if the WG solenoid is moving and its hoses are connected with no leaks ( and are connected the right way round) then that aspect should be OK

the other possibilty is the MAP ( manifold pressure sensor) mounted on the inlet manifold is having issues

check its connection for corrosion and the wire for damage, if this looks OK then Ideally use a scan tool to read off what its showing with the engine off and the engine running as off should be about 1000mbar and engine idling about 500 mbar

Customer: replied 9 months ago.
i pull out the battery to swap the engine last week after everything finish i start the car. check engine code 3100 2abc ,i have 4 map sensor with me
Expert:  Matt replied 9 months ago.


the 2 aBC code does point to the MAP sensor fault?

did you transfer over the original MAP sensor for the wiring loom and the car ? as soemtimes the MAP sensor is a different part number for different engine series?

If the ECU detects any sensor its not happy with then the 1st thing it does is limit the boost pressure

Customer: replied 9 months ago.
i transfer all to the new engine., and always have that code.and,sec i switch another 2 map from new engine still the same
Customer: replied 9 months ago.
when i pull the wire ans start the car right the way have another code say manifold absolute pressure desactive . and also i fund out inside the centre work too
Expert:  Matt replied 9 months ago.


I'm going to have to opt out as I don't have access to the level of detail required

hopefully another expert will be able to assist

good luck

Customer: replied 9 months ago.
ok thx